Battery pack, electronic equipment system and method of detecting loading of battery pack technical field

ABSTRACT

A battery pack 2 is detachably loaded with respect to an electronic equipment 1 through an electric connecting portion 3 to thereby deliver power. A CPU 2f of the battery pack 2 detects signal states of communication lines by using communication lines, e.g., data lines 3h, 3f and clock lines 3i, 3g for informing information between the battery pack 2 and the electronic equipment 1, whereby the battery pack 2 detects whether the battery pack is in the state electrically connected to the connecting portion of the electronic equipment 1 or in the state electrically detached from the connecting portion of the electronic equipment 1. Thus, the number of connecting terminals used in electrically connecting the battery pack with respect to the electronic equipment is reduced. As a result, miniaturization can be realized and there can result less unsatisfactory terminal contact.

TECHNICAL FIELD

This invention relates to a battery pack to be loaded into electronicequipment, e.g., a portable personal computer, to supply power, and alsorelates to an electronic equipment system having a battery pack andelectronic equipment, as well as to a loading detecting method for thebattery pack, which detects whether or not the battery pack is loaded inthe electronic equipment.

BACKGROUND ART

Electronic equipment is being increasingly provided as portableelectronic equipment, e.g., the so-called notebook-type personalcomputers, information terminals, video tape recorders, sound recordersand/or portable telephones, etc. and there are, e.g., electric bicyclesprovided with a motor for power assist, etc.

Such electronic equipment is adapted so that a battery pack (also calleda battery package) is loaded into the equipment for the purpose ofsupplying power from the battery pack for operating the equipment.

An explanation will be given by taking the example of a notebookpersonal computer and battery pack therefor as an example of the priorart.

The function to detect whether or not a conventional battery pack iselectrically connected to the body of the notebook personal computer beexplained with reference to FIG. 1.

FIG. 1 shows a portion of the circuit configuration of an interface of anotebook personal computer 1000 and a battery pack 1002.

The notebook personal computer 1000 and the battery pack 1002 aredetachably connected by a connecting portion 1003. A battery plusterminal (Batt+terminal) 1003a and a battery minus terminal(Batt-terminal) 1003e are connecting portions for power supply of thenotebook personal computer 1000 and the battery pack 1002. The notebookpersonal computer 1000 can collect respective information of the batterypack 1002 such as charge/discharge current, battery voltage andcapacity, etc. through a communication line from the battery pack 1002.

In FIG. 1, there is shown a communication system of the two wire typehaving a data line and a clock line, and the data line and the clockline of the notebook personal computer 1000 and the battery pack 1002are respectively connected by a data terminal 1003b and a clock terminal1003c. A B-IN terminal 1003d is a connecting portion of a detection line1002e relating to the loading state of the battery pack 1002 in the bodyof the notebook personal computer 1000.

Reference numeral 1001a indicates a 5V power supply line of the notebookpersonal computer 1000, reference numeral 1001f indicates acommunication LSI (Large Scale Integrated) Circuit of the notebookpersonal computer 1000, reference numeral 1001b indicates a pull-upresistor Rn 1 (e.g., 4.7 kΩ) of the data line, and reference numeral1001c indicates a pull-up resistor Rn2 (e.g., 4.7 kΩ) of the clock line.Reference numeral 1001d indicates a pull-down resistor Rn3 (e.g., 10 kΩ)for allowing the loading state detection line 1002e of the battery pack1002 to be at an L level (low).

Reference numeral 1002a indicates a 5V power supply line of the batterypack 1002, and reference numeral 1002f indicates a CPU (CentralProcessing Unit) for charge/discharge control of the battery pack 1002,communication with the notebook personal computer 1000 and variouscalculations. Reference numeral 1002d indicates a pull-up resistor Rp3(e.g., 1 MΩ) of the loading state detection line of the battery pack1002.

Let us consider the case where an AC adapter (A.C. current adapter) isnot connected to the notebook personal computer 1000 and the 5V powersupply line 1001a of the notebook personal computer 1000 has a highimpedance. Before loading of the battery pack 1002 is detected, the CPU1002f of the battery pack 1002 does not deliver power to the notebookpersonal computer 1000. When the battery pack 1002 is loaded, the signallevel of the loading state detection line 1002e of the battery pack 1002shifts from the H level (high) to the L level (low) by a resistor (Rn3)1001d of the notebook personal computer 1000, and the CPU 1002f thusdetects loading of the battery pack 1002. When such loading is detected,the battery pack 1002 delivers power to the notebook personal computer1000.

In the case where the battery pack 1002 is taken out of the notebookpersonal computer 1000, the loading state detection line 1002e isdisconnected from the pull-down resistor(Rn3) 1001d, and its signallevel shifts from the L level to the H level by the pull-up resistor(Rp3) 1002d.

In the case where, for the purpose of reducing current consumption, thebattery pack 1002 is not loaded into the notebook personal computer1000, or in the case where the notebook personal computer 1000 is in asleep state even if the battery is loaded, power supply to a portion ofthe circuit within the battery pack 1002 is interrupted to reducecurrent consumption.

The charge/discharge operation of the battery pack 1002 is effected bythe loading state, when the battery is not loaded, the battery pack 1002inhibits the charge/discharge operation, but when it is loaded, itenables charge/discharge operation if the battery pack 1002 in a normalstate.

Detection that the notebook personal computer 1000 is in a sleep stateduring loading is carried out by allowing the CPU 1002f of the batterypack 1002 to detect that the signal level of the communication line isnot changed for a predetermined time or longer.

The battery pack 1002 serves to apply a latch for overcurrent protectionso that charge/discharge operation is disabled. However, in the casewhere overcurrent is detected, the latch for overcurrent protection isreleased when the battery pack 1002 is taken out from the notebookpersonal computer 1000.

Further, the loaded battery pack 1002 does not deliver power to thenotebook personal computer 1000 until it recognizes that the batterypack 1002 has been loaded (it is in the chargeable/dischargeable state).In addition, in the case where the battery pack 1002 is taken out, itdoes not inhibit charge/discharge operation until it recognizes that itis taken out except for an extraordinary state such as overcurrent,overdischarge or overcharge, etc.

For the above reasons, the function to detect the electrical loadingstate with respect to the connecting portion 1003 of the battery pack1002 is important.

Meanwhile, as shown in FIG. 1, the connecting portion 1003 between thenotebook personal computer 1000 and the battery pack 1002 requires fiveterminals in total for the battery plus terminal 1003a, data terminal1003b, clock terminal 1003c, B-IN terminal 1003d and the battery minusterminal 1003e. Accordingly, in the case where the battery pack 1002 isconnected by the connecting portion 1003 with respect to the notebookpersonal computer 1000, unless these five terminals are electricallysecurely connected, it is impossible to adequately deliver power to thenotebook personal computer 1000 from the battery pack 1002.

If the number of these terminals of the connecting portion 1003 can bereduced, particularly if the B-IN terminal 1003d can be eliminated, thenumber of output terminals at the connecting portion 1003 is reduced.Thus, the battery pack 1002 can be more reliably electrically connectedwith respect to the notebook personal computer 1000, and miniaturizationof the connecting portion can be realized and there can result lessunsatisfactory terminal contact.

SUMMARY OF THE INVENTION

This invention has been made in view of the above-described problems,and its object is to provide a battery pack, an electronic equipmentsystem and a method of detecting loading of the battery pack such thatthe number of connecting terminals used in electrically connecting thebattery pack with respect to the electronic equipment is reduced so thatminiaturization can be realized and there can result less unsatisfactoryterminal contact.

In order to solve the problems as described above, this invention isdirected to the configuration in which the battery pack is detachablyloaded through an electric connecting portion to thereby deliver power,wherein the battery pack detects, by using a communication line forcarrying out transmission/reception of information between the batterypack and the electronic equipment, whether the battery pack is in thestate electrically connected to the connecting portion of the electronicequipment or the battery pack is in the state electrically detached fromthe connecting portion of the electronic equipment.

In this invention, the communication line for transmitting informationbetween the battery pack and the electronic equipment is utilized.Namely, the battery pack can detect, on the basis of the state of thesignal of this communication line, whether the battery pack is in thestate electrically connected to the connecting portion of the electronicequipment or the battery pack is in the state electrically detached fromthe connecting portion of the electronic equipment.

In a more practical sense, as the communication line, there arementioned a data line for carrying out transmission/reception of databetween the battery pack and the electronic equipment and a clock linesupplied with a clock signal from the electronic equipment. In thiscase, it is possible to detect, on the basis of a change of the signallevel of the clock line at the time of a first state where theelectronic equipment is supplied with power and communication is notcarried out between the battery pack and the electronic equipment, achange of the signal level of the data line or the clock line at thetime of a second state where the electronic equipment is supplied withpower and communication is being carried out between the battery packand the electronic equipment and a change of the signal level of thedata line or the clock line at the time of a third state where theelectronic equipment is not supplied with power, whether the batterypack is in the state electrically connected to the connecting portion ofthe electronic equipment or in the state electrically detached from theconnecting portion of the electronic equipment.

Thus, the number of terminals for detection of loading of the batterypack which were required separately in the prior art can be reduced.Accordingly, miniaturization can be realized and there can result lessunsatisfactory contact of terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electrical diagram showing an example of a conventionalelectronic apparatus.

FIG. 2 is a perspective view showing an example applied to a notebookpersonal computer as an embodiment of a battery pack and electronicequipment of this invention.

FIG. 3 is an electrical diagram showing a connection example of abattery pack and its electric connecting portion in the notebookpersonal computer of FIG. 2.

FIG. 4 is an electrical diagram showing another embodiment of thisinvention.

FIG. 5 is an electrical diagram showing a further embodiment of thisinvention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of this invention will now be described in detailin accordance with the attached drawings.

Since the embodiments described below are preferred practical examplesof this invention, various technical limitations are found in theseembodiments. However, the scope of this invention is not limited tothese examples as long as there is no description to the effect thatthis invention is particularly limited in the following explanation.

FIG. 2 shows, as an embodiment of this invention, an example in whichthis invention is applied to a notebook type personal computer 1 and abattery pack 2. A body 105 of this notebook personal computer 1 includesa key board 101, a display 102, a slot 103 for a PC card, and a drive104 for a CD-ROM (Read Only Memory utilizing compact disc), etc.

The battery 2 is detachably loaded into the body 105 so that it can beelectrically connected thereto though the electric connecting portion 3.This battery pack 2 serves to deliver power for operation to thenotebook personal computer 1 and is called a battery package. As anadditional battery, e.g., a secondary battery, a lithium ion secondarybattery may be used.

It is to be noted that, as the battery pack 2, a secondary battery orother kind of battery, e.g., lithium ion secondary battery, lead storagebattery (the type used in an automotive vehicle), Ni--Cd battery(Nickel-Cadmium battery), Ni-hydrogen battery (Nickel-hydrogen battery),Ni--Zn battery (Nickel Zinc storage battery), polymer battery, Zn-airbattery (Zinc-air battery), etc. may be employed.

FIG. 3 shows the state where the battery pack 2 is connected to thenotebook personal computer 1 though the connecting portion 3 in theembodiment of this invention.

The notebook personal computer 1 shown in FIG. 3 is the system in whichonly one AC adapter (A.C. power adapter) or the battery pack 2 can beloaded.

The notebook personal computer 1 includes a communication circuit LSI(Large Scale Integrated Circuit) (called a communication control unit asoccasion may demand) 1f, and two pull-up resistors including a pull-upresistor (Rn1) 1b and a pull-up resistor (Rn2) 1c, etc. Thecommunication circuit LSI 1f is connected between, e.g., a power supplyline 1a of 5V and a ground line (GND) 10, and one respective end of twopull-up resistors (Rn1) 1b and (Rn2) 1c are connected to the powersupply line 1a of 5V.

The other end of the pull-up resistor (Rn1) 1b is connected to a dataline 3h of the communication LSI 1f, and the other end of the pull-upresistor (Rn2) 1c is connected to a clock line 3i of the communicationLSI 1f. The data line 3h and the clock line 3i are respectivelyconnected to a data terminal 3b and a clock terminal 3c of theconnecting portion 3a. Battery lines 3j and 3k of the notebook personalcomputer 1 side are respectively connected to a battery plus terminal(Batt+terminal) 3a and a battery minus terminal (Batt-terminal) 3e. Inthis example, the battery line 3k connected to the battery minusterminal (Batt-terminal) 3e serves as the ground line (GND) 10.

Moreover, at the notebook personal computer 1, various peripheraldevices 17, and memory 18 such as ROM (Read Only Memory) and RAM (RandomAccess Memory), etc. are connected to a bus line BUS of the main CPU(Central Processing Unit), and the communication LSI 1f is connected tothis bus line BUS. A power switch 13 is provided at a power controlcircuit 12 so that power ON/OFF control is carried out, and is suppliedwith commercial AC power from a power supply plug 15 through an ACadapter 14 so that power from the battery pack 2 is delivered throughthe battery lines 3j and 3k. In addition, charge current supply to thebattery pack 2 is carried out though the battery lines 3j and 3k.

On one hand, the battery pack 2 includes a CPU (Central Processing Unit)2f serving as a control unit, a single pull-up resistor (Rp11) 2b, and apull-down resistor (Rp21) 2c. The pull-up resistor 2b is connectedbetween a data line 3f of the CPU 2f and a power supply line 2a of 5V. Adata line 3f and a clock line 3g of the CPU 2f can be respectivelyconnected to the data terminal 3b and the clock terminal 3c of theconnecting portion 3a. The data line 3f is connected to the other end ofthe pull-up resistor 2b, the clock line 3g is connected to one end ofthe pull-down resistor 2c, and the other end of the pull-down resistor2c is connected to the ground line 10.

Moreover, a battery cell group composed of, e.g., four battery cells21a, 21b, 21c and 21d connected in series is accommodated within thebattery pack 2. The plus side of this battery cell group is connected tothe battery plus terminal (Baa+terminal) 3a for external connectionthrough a switching element, and the minus side thereof is connected tothe battery minus terminal (Batt-terminal) 3e for external connection.In order to measure voltages of respective battery cells 21a, 21b, 21cand 21d of the group of battery cells, there are provided a multiplexer(MPX) 22 and an operational amplifier 23. When a battery cell selectcontrol signal from the CPU (control unit) 2f is sent to the multiplexer22 through a control line 44, the multiplexer 22 selects any one of thefour battery cells 21a, 21b, 21c and 21d to send its terminal voltage tothe operational amplifier 23. Output from this operational amplifier 23is sent to the CPU 2f though a voltage measurement signal line 45, andis caused to undergo A/D (Analog/Digital) conversion within the CPU 2f.Thus, the battery cell terminal voltage is taken thereinto as a digitalvalue. A resistor 24 for current measurement is inserted and connectedat, e.g., the minus side of the battery cell group. A voltagecorresponding to current value flowing in this resistor 24 is detectedby an operational amplifier 25, and is sent to the CPU 2f through acurrent measurement signal line 46. The voltage thus obtained is causedto undergo A/D (Analog/Digital) conversion within the CPU 2f, andcurrent value thus measured is taken as a digital value. The multiplexer22 and the operational amplifiers 23 and 25 are supplied with powerthrough a power saving switch 26 from the plus side of the battery cellgroup. This switch 26 is subjected to ON/OFF control by a power savingcontrol signal delivered through a power saving control line 43 from theCPU 2f. Moreover, a regulator circuit 29 for 5V power supply isconnected to the plus side of the battery cell group, and the outputfrom the 5V power regulator circuit 29 is delivered to the power supplyline 2a of 5V.

Further, a FET 31 serving as a switching element for the Chargeoperation and a FET 32 serving as a switching element for the Dischargeoperation are inserted and connected in series between the battery plusterminal (Batt+terminal) 3a of the battery pack 2 and the plus side ofthe battery cell group, and diodes 33 and 34 are respectively connectedin parallel with these FETs 31 and 32. The FET 31 for charge operationis caused to undergo ON/OFF control by a driver 35. This driver 35 isdriven by a control signal delivered through a charge control line 41from the CPU 2f. On the other hand, the discharge FET 32 is caused toundergo ON/OFF control by a driver 36, and this driver 36, is driven bya control signal delivered through a discharge control line 42 from theCPU 2f.

In FIG. 3, the impedance of the 5V power supply line 1a is caused to behigh, the data line 3f of the battery pack 2 is pulled up by the pull-upresistor 2b (e.g., 1 MΩ) so that there results a potential on the 5Vpower supply line 2a of the battery pack 2, and the clock line is pulleddown by the pull-down resistor 2c (e.g., 10 MΩ) so that there results apotential on the ground line 10.

Namely, in this example, when an example of respective resistor valuesis taken, the pull-up resistor lb of the notebook personal computer 1 iscaused to be 4.7 kΩ, the pull-up resistor 1c thereof is caused to be 4.7kΩ, the pull-up resistor 2b of the battery pack 2 is caused to be 1 MΩ,and the pull-down resistor 2c is caused to be 10 MΩ.

This notebook personal computer 1 is configured so that only one ACadapter or battery pack can be loaded and the 5V power supply line 1ahas high impedance. In this case, the state where the battery pack 2 iselectrically detached from the connecting portion 3 and the computer isoperative by power supply from the AC adapter 14 is assumed. In thenotebook personal computer 1 in such a state, e.g., the body 105 of FIG.2 is in a sleep state and data terminal 3b and clock terminal 3c of thecommunication LSI 1f are held at 5V of the 5V power supply line 1a ofhigh impedance as described above and so is in a communication standbystate.

Namely, since the data line 3h which is pulled up by the pull-upresistor 1b and the clock line 3i which is pulled up by the pull-upresistor 1c are held at 5V, when the battery pack 2 is inserted so thatit is electrically connected by the connecting portion 3, signal levelof the pulled up data line 3h is not changed, remaining at the H level(High level), but the signal level of the pulled down clock line 3ichanges from the L level (Low level) to the H level. By detecting thislevel change by the clock terminal 3g of the CPU 2f of the battery pack2, the battery pack 2 detects the insertion state into the notebookpersonal computer 1.

In the notebook personal computer 1 in which the battery pack 2 isdetached and is operative by the AC adapter 14, in the case wheresynchronous communication of, e.g., data of 8 bits is carried out atspeed (rate) of 9600 bps in the communication operating state, sincecommunication data signals appear on both the data line 3h and the clockline 3i, their signal levels change from the H level to the L level, orfrom the L level to the H level.

In view of the above, when the battery pack 2 is electrically insertedinto the connecting portion 3 of the notebook personal computer, thesignal level is changed between H/L in accordance with communicationdata appears on the data line 3h or the clock line 3i. By detecting thepresence/absence of signal level change between H/L, it is possible todetect that the battery pack 2 has been loaded into the connectingportion 3. In this case, where attention is paid only to the signallevel, the falling or rising edge when the signal level of the data line3h changes from the H level to the L level or the clock line 3i changesfrom the L level to the H level is detected at the data terminal 3f orthe clock terminal 3g of the CPU 2f of the battery pack 2, therebymaking it possible to detect that the battery pack 2 has beenelectrically inserted into the connecting portion 3.

In the case where both the battery pack 2 and the AC adapter 14 aredetached from the notebook personal computer 1, the 5V power supply line1a of the notebook personal computer 1 is not held at 5V. When thebattery pack 2 is inserted into the notebook personal computer 1, the 5Vpower supply line 2a and ground line 10 of the battery pack 2 areelectrically connected through the pull-up resistor 2b, pull-up resistor1b, pull-up resistor 1c and the pull-down resistor 2c. For this reason,the voltage level on the data line 3f of the battery pack 2 is expressedas follows.

    (4.7 kΩ+4.7 kΩ+10 MΩ)×5/(1 MΩ+4.7 kΩ±4.7 kΩ+10 MΩ)V

The voltage level of the clock line 3g is expressed as 10 MΩ×5/(1 MΩ+4.7kΩ+4.7 kΩ+10 MΩ)V. By insertion of the battery pack 2, the signal levelof the data line 3f is not changed in the state remaining at the Hlevel, and signal level of the clock line 3g changes from the L level tothe H level. Accordingly, this level change is detected by the clockterminal 3g of the CPU 2f to thereby detect insertion of the batterypack 2.

When the battery pack 2 is taken out of the notebook personal computer1, since the signal level of the data line 3f of the battery pack 2 ispulled up, it is caused to be at the H level, and since the signal levelof the clock line 3g is pulled down, it is caused to be at the L level.In view of this, if the signal levels of the data line 3f and the clockline 3g of the battery pack 2 are respectively at the H level and the Llevel for a predetermined time or longer (e.g., 1 sec or more), it isjudged that the battery pack 2 has been detached from the notebookpersonal computer 1.

As described above, the data line and clock line serving as thecommunication line are used to judge the electrical insertion ortaking-out with respect to the notebook personal computer 1 of thebattery pack 2, thereby making it possible to eliminate the B-INterminal which was conventionally required to serve as a detectionterminal for insertion or removal of the battery.

In the configuration of this electronic equipment, it is preferable tocarry out detection of the electric loading state and non-loading stateof the battery pack 2 by a change of the signal level of the data lineor clock line in a manner of state classification as described below ina more practical sense.

As the initial state at the time of detection of loading state, it isclassified into the following three cases.

(1) The case where the notebook personal computer 1 is supplied withpower from the AC adapter 14 or the battery pack 2, etc., andcommunication of the notebook personal computer 1 is in a standby state.

(2) The case where the notebook personal computer 1 is supplied withpower from the AC adapter 14 or the battery pack 2, etc., and thenotebook personal computer 1 is in a communicating state.

(3) The case where the notebook personal computer 1 is not supplied withpower from the AC adapter 14 or the battery pack 2, etc.

The above-described respective states (1), (2), (3) will now beexplained with reference to the Table 1 and FIG. 3.

                  TABLE 1                                                         ______________________________________                                        STATE OF        INSERTION                                                     BATTERY PACK    (LOADING)   TAKING OUT                                        ______________________________________                                        (A)  STATE (1)      DATA LINE: H → H → H                             COMMUNICATION  CLOCK LINE: L H → L                                     STANDBY AT                                                                    TIME OF POWER                                                                 SUPPLY                                                                   (B)  STATE (2) POWER                                                                              DATA LINE: H → H/L → H                           SUPPLY         CLOCK LINE: L→ H/L → L                           COMMUNICATING                                                                 SATE                                                                     (C)  STATE (3) NO   DATA LINE: H → H → H                             POWER SUPPLY   CLOCK LINE: L → H → L                       ______________________________________                                    

State (1)

Since the notebook personal computer 1 is already supplied with powerfrom the battery pack 2 as indicated by (A) of the Table 1, the 5V powersupply line 1a is held at 5V. For this reason, at the time ofcommunication standby, in the case where both signal levels of the dataline 3f and the clock line 3g are at the H level (5V), when the batterypack 2 is electrically inserted into the connecting portion 3, thesignal level of the data line 3f is not changed and remains at the Hlevel, but the signal level of the clock line 3g changes from the Llevel to the H level. If this change is detected, the CPU 2f of thebattery pack 2 judges that the battery pack 2 has been electricallyinserted.

In the case where the battery pack 2 is taken out from the notebookpersonal computer 1 the signal levels of the data line 3f and the clockline 3g of the battery pack 2 are respectively at the H level and the Llevel. Accordingly, when it is detected that the signal level of thedata line 3f is at the H level and the signal level of the clock line 3gis at the L level for a predetermined time or more, the battery pack 2judges that it has been taken out.

State (2)

In the case where the notebook personal computer 1 is communicating asindicated by (B) of the Table 1, signal levels of the data line 3h andthe clock line 3i of the notebook personal computer 1 momentarily changefrom the L level to the H level and from the H level to the L level(indicated by H/L in the Table). Accordingly, if, when the battery pack2 is inserted, the signal level of data line 3f of the battery pack 2changes from the H level to the L level and the signal level of theclock line 3g changes from the L level to the H level, the CPU 2f of thebattery pack 2 judges by this change that the battery pack 2 has beeninserted.

In the case where the battery pack 2 is taken out of the notebookpersonal computer 1, signal levels of the data line 3f and the clockline 3g of the battery pack 2 are respectively caused to be at the Hlevel and the L level. Accordingly, if the signal level of the data lineis at the H level and the signal level of the clock line is at the Llevel for a predetermined time or longer, the CPU 2f of the battery pack2 judges that the battery pack 2 has been taken out.

State (3)

When the battery pack 2 is inserted into the notebook personal computer1 as indicated by (C) of the Table 1, the 5V power supply line 1a andthe ground line 10 are connected through the pull-up resistor 2b,pull-up resistor 1b, pull-up resistor 1c, and the pull-down resistor 2c.If the pull-up resistor 2b is selected so that its resistance value issufficiently larger than that of the pull-up resistor 1b and the pull-upresistor 1c and the pull-down resistor 2c is selected so that itsresistance value is equal to 10 times larger than that of the pull-upresistor 2b, signal levels of the data line 3f and the clock line 3g arecaused to be at the H level. In this case, the signal level of the dataline 3f is not changed in the state remaining at the H level, but signallevel of the clock line 3g changes from the L level to the H level. Forthis reason, insertion of the battery pack 2 can be judged.

In the case where the battery pack 2 is taken out of the notebookpersonal computer 1 in a manner opposite to the above, signal levels ofthe data line 3f and the clock line 3g of the battery pack 2 arerespectively caused to be at the H level and the L level. Accordingly,if it is detected that the signal level of the data line 3f is at the Hlevel and the signal level of the clock line 3g is at the L level for apredetermined time or longer, the CPU 2f of the battery pack 2 judgesthat the battery pack 2 has been taken out.

Another embodiment of the electronic equipment of this invention willnow be described with reference to FIG. 3.

In FIG. 3, the impedance of the 5V power supply line 1a of the notebookpersonal computer 1 is caused to be high, the data line 3h of thebattery pack 2 is pulled up by the pull-up resistor (Rp11) (e.g., IMΩ)2b so that the potential of the 5V power supply line 2a is provided, andthe clock line 3g is pulled down by the pull-down resistor (Rp21) (e.g.,100 kΩ) 2c so that the potential of the ground line 10 is provided.

The resistance value (e.g., 100 kΩ) of this pull-down resistor (Rp21) 2cis lower as compared to the resistance value (e.g., 10 MΩ) of thepull-down resistor Rp21 in the above-described embodiment, and has avalue which is about one/tenth greater than the resistance value (e.g.,1 MΩ) of the pull-up resistor (Rp11) 2b of the data line 3h. In thestate where battery pack 2 is inserted into the notebook personalcomputer 1, the impedance of the 5V power supply line 1a is caused tocorrespond to low impedance.

In this configuration, by a change of the signal level of the data lineor clock line, the battery pack 2 carries out detection of loadingstates (1), (2), (3) as indicated by the following Table 2.

                  TABLE 2                                                         ______________________________________                                        STATE OF        INSERTION                                                     BATTERY PACK    (LOADING)   TAKING OUT                                        ______________________________________                                        (A)  STATE (1)      DATA LINE: H → H → H                             COMMUNICATION  CLOCK LINE: L → H → L                            STANDBY AT                                                                    TIME OF POWER                                                                 SUPPLY                                                                   (B)  STATE (2)      DATA LINE: H → H/L → H                           POWER          CLOCK LINE: L → H/L → L                          SUPPLY                                                                        COMMUNICATING                                                                 STATE                                                                    (C)  STATE (3) NO   DATA LINE: H → L → H                             POWER SUPPLY   CLOCK LINE: L → L → L                       ______________________________________                                    

State (1)

This state is the same as the state (1) of (A) of the Table 1.

State (2)

This state is the same as the state (2) of (B) of the Table 1.

State (3)

When the battery pack 2 of FIG. 3 is inserted into the notebook personalcomputer 1 as indicated by (C) of the Table 1, the 5V power supply line1a and the ground line 10 are connected through the pull-up resistor 2b,pull-up resistor 1b, pull-up resistor 1c, and the pull-down resistor 2c.The pull-up resistor 2b is selected so that its resistance value issufficiently greater than that of the pull-up resistor 1b and thepull-up resistor 1c, and the pull-down resistor 2c is selected so thatits resistance value is a value about 1/10 times greater than that ofthe pull-up resistor 2b. For this reason, signal levels of the data line3f and the clock line 3g are caused to be at the L level. The signallevel of the clock line 3g is not changed and remains at the L level.However, since the signal level of the data line changes from H to L,insertion of the battery pack 2 can be judged by this change.

In the case where the battery pack 2 is taken out of the notebookpersonal computer 1, the signal levels of the data line 3f and the clockline 3g of the battery pack 2 are respectively caused to be at the Hlevel and the L level. Accordingly, if it is detected that the signallevel of the data line 3f is at the H level and the signal level of theclock line 3g is at the L level for a predetermined time or longer, theCPU 2f of the battery pack 2 judges that the battery pack 2 has beentaken out.

Moreover, by also employing, in place of the configuration of FIG. 3, anapproach in which the impedance of the 5V power supply line of thenotebook personal computer is caused to be low (e.g., a resistor of 100kΩ is inserted between the 5V power supply line and the ground line),and the impedance of the pull-down resistor Rp21 of the clock line ofthe battery pack is caused to be value about 10 times greater than thatof the pull-up resistor Rp11 of data line, it is possible to detect theloading state by a similar operation.

In this case, in the above-described embodiment shown in FIG. 3, thedata line 3f of the CPU 2f of the battery pack 2 is connected to the 5Vpower supply line 2a through the pull-up resistor (Rp11) 2b, and theclock line 3g is connected to the ground line (GND) 10 through thepull-down resistor (Rp21). In a manner opposite to the above, namely,the data line 3f may be connected to the ground line through thepull-down resistor, and the clock line 3g may be connected to the 5Vpower supply line through the pull-up resistor. In this case, loadingdetection of the battery pack can be similarly carried out except thatthe signal state of data line in the Table 1 and the Table 2 and thesignal state of clock line are opposite to each other.

A further embodiment of the electronic equipment of this invention willnow be described with reference to FIG. 4 and the Table 3.

In FIG. 4, the notebook personal computer 1 includes a resistor (Rnx)1h, pull-up resistor (Rn1) 1b, and an LSI circuit 1f for communication,etc. One respective end of the resistor 1h and the pull-up resistor 1bare connected to the 5V power supply line 1a, and the other end of theresistor 1h and resistor 1b are connected to the communication LSIcircuit 1f. The control LSI 1f is also connected to the ground line 10(called the battery line 3k as occasion may demand). The other end ofthe pull-up resistor 1b is connected to the data line 3h ofcommunication LSI 1f, and this data line 3h is connected to the dataterminal 3b. The battery line 3j is connected to the battery terminal3a, and the ground line 10 (battery line 3k) is connected to the batteryterminal 3e.

The connecting portion 3 has only three terminals in total including thebattery terminals 3a, 3e and the data terminal 3b.

On the other hand, the battery pack 2 includes the pull-up resistor(Rp11) 2b and CPU 2f, and the 5V power supply line 2a is connected atone end of the pull-up resistor 2b. The other end of the pull-upresistor 2b is connected to the data line 3f of the CPU 2f. The otherend of the CPU 2f is connected to the ground line 10.

As stated above, in the embodiment of the electronic equipment of FIG.4, the connecting portion 3 includes three terminals 3a to 3e, and thecommunication LSI 1f and the CPU 2f include only data lines 3h, 3f anddoes not have a clock line. Namely, the electronic equipment of FIG. 4employs the so-called one wire type communication system, but isdifferent in that the embodiment of FIG. 3 employs so-called two-wiretype communication system having the data line and the clock line.

In FIG. 4, the resistor Rnx (e.g., 100 kΩ) is inserted between the 5Vpower supply line 1a and the ground line 10 to allow the impedance ofthe 5V power supply line 1a of the notebook personal computer 1 to be alow impedance, and to the pull-up data line 3f of the battery pack 2 bythe pull-up resistor (e.g., 1 MΩ) 2b so that the potential of the 5Vpower supply line 2a is provided.

In the configuration shown in FIG. 4, the battery pack 2 carries outdetection of the loading state by a change of the signal level of thedata line 3f in a manner as shown in the Table 3.

                  TABLE 3                                                         ______________________________________                                        STATE OF        INSERTION                                                     BATTERY PACK    (LOADING)   TAKING OUT                                        ______________________________________                                        (A)  STATE (1)      DATA LINE: H → L → H                             COMMUNICATION                                                                 STANDBY AT                                                                    TIME OF POWER                                                                 SUPPLY                                                                   (B)  STATE (2)      DATA LINE: H → H/L → H                           POWER                                                                         SUPPLY                                                                        COMMUNICATING                                                                 STATE                                                                    (C)  STATE (3) NO   DATA LINE: H → L → H                             POWER SUPPLY                                                             ______________________________________                                    

State (1)

The data signal at the time of the communication standby state of thenotebook personal computer 1 is assumed to be at the L level asindicated by (A) of the Table 3. Thus, when the battery pack 2 isinserted into the notebook personal computer 1, the signal level of dataline 3f of battery pack 2 changes from the H level to the L level. Inthis case, by this change, the CPU 2f of the battery pack 2 judges thatthe battery pack 2 has been inserted.

In the case where the battery pack 2 is taken out from the notebookpersonal computer 1, the signal level of the data line 3f of the batterypack 2 is caused to be at the H level. Accordingly, if the CPU 2f of thebattery pack 2 detects that the signal level of the data line 3f iscaused to be at the H level for a predetermined time or longer, itjudges that the battery pack 2 has been taken out.

State (2)

In the case where the notebook personal computer 1 is communicating asindicated by (B) of the Table 3,the signal level of that data line 3fchanges (H/L) from the H level to the L level, or from the L level tothe H level. For this reason, when the battery pack 2 is inserted, thereare instances where signal level of data line 3f of battery pack 2changes from the H level to the L level. The CPU 2f detects this changeto thereby detect that the battery pack 2 has been inserted.

In the case where the battery pack 2 is taken out from the notebookpersonal computer 1, the signal level of the data line 3f of the batterypack 2 is caused to be at the H level. Accordingly, if it is detectedthat the signal level of the data line 3f is caused to be at the H levelfor a predetermined time or longer, the battery pack judges that it hasbeen taken out.

State (3)

When the battery pack 2 is inserted into the notebook personal computer1 as indicated by (C) of FIG. 3, the 5V power supply line 2a and theground line 10 of the battery pack 2 are connected by the pull-upresistor 2b and the resistor Rnx. For this reason, when the pull-upresistor 2b is selected so that its resistance value is sufficientlygreater than that of the resistor Rnx, the signal level of the data line3f changes from the H level to the L level as the result of the factthat the battery pack 2 is inserted. By this change, the CPU 2f of thebattery pack 2 can judge that the battery pack 2 has been inserted.

In accordance with the embodiment of this invention, it becomes possibleto detect electrically the insertion and removal with respect to thenotebook personal computer 1 of the battery pack 2 by the communicationline. As a result, the necessity of providing a dedicated terminal fordetecting the loading state which is conventionally required iseliminated. Thus, the number of terminals can be reduced, andminiaturization of connector can be realized and there can result lessunsatisfactory contact.

It is to be noted that, similarly to the prior art, the battery pack 2detects the loading state to thereby control the supply of power fromthe battery pack 2 to the notebook personal computer 1, or to carry outcharge/discharge control.

Specifically, in the case where, for the purpose of reducing currentconsumption, the battery pack 2 is not loaded into the notebook personalcomputer 1 or the notebook personal computer 1 is in a sleep state evenif the battery is loaded, the supply of power to a portion of thecircuit within the battery pack 2 is interrupted to reduce currentconsumption.

A difference in the charge/discharge operation of the battery pack 2 iseffected by the loading state, when the battery pack 2 is not loaded, itinhibits the charge/discharge operation, but when the battery pack 2 isloaded, if the battery pack 2 is in the normal state, thecharge/discharge operation can be made.

Detection that the notebook personal computer 1 is in the sleep stateduring loading is carried out by allowing the CPU 2f of the battery pack2 to detect that the signal level of the communication line is notchanged for a predetermined time or more.

The battery pack 2 applies a latch for overcurrent protection so thatthe charge/discharge operation cannot be performed in the case whereovercurrent is detected, the latch for overcurrent protection isreleased when the battery is taken out of the notebook personal computer1.

Further, the battery pack 2 does not supply power to the notebookpersonal computer 1 until the battery pack 2 is loaded(chargeable/dischargeable state). In addition, in the case where thebattery pack 2 is taken out, the charge/discharge operation is notinhibited until the battery pack 2 recognizes that it has been taken outexcept for the extraordinary state such as overcurrent, overdischarge orovercharge, etc.

Control of such charge/discharge operation is carried out by allowingthe CPU 2f of the battery pack 2 of FIG. 3 to carry out ON/OFF controlof FETs 31 and 32 through control lines 41 and 42 and through drivers 35and 36. In addition, in the case where the power supply from the batterypack 2 to the notebook personal computer 1 is not carried out, the CPU2f sends a power saving control signal to the switch 26 through thecontrol line 43 to cut OFF the power supply to the multiplexer 22 andthe operational amplifiers 23 and 25 to thereby carry out a control suchthat there results the power saving state.

A further embodiment of the electronic equipment of this invention willnow be described with reference to FIG. 5.

The embodiment of FIG. 5 is substantially similar to the embodiment ofFIG. 3, but a thermistor 30 for temperature compensation is provided inaddition to the embodiment of FIG. 3. This thermistor 30 is disposedbetween the 5V power supply line 1a and the ground line 10 of thenotebook personal computer 1 through a resistor 1g and a terminal 3n.

In the configuration of FIG. 3, in the case where the pull-down resistor(Rp21) 2c is provided, e.g., the pull-down resistor of the embodimenthaving relatively low impedance of about 100 kΩ, the signal level isdropped with respect to the ground 10 through the clock line 3i, clockline 3g and the pull-down resistor (Rp21) 2c from the data line 3h ofthe communication LSI circuit 1f, whereby the signal level of the dataterminal 3b changes from the H level to the L level.

On the contrary, in the embodiment of FIG. 5, the data line 3f is pulleddown with respect to the ground 10 through the resistor (Rn3) 1g,terminal 3n and the thermistor 30. Thus, when the battery pack 2 isloaded into the notebook personal computer 1, the signal level of thepower supply line 1a changes from the H level to the L level. For thisreason, the CPU 2f of the battery pack 2 detects the change of thesignal level (a change from the H level to the L level) of the data line3f, thereby making it possible to detect that the battery pack 2 hasbeen inserted into the notebook personal computer 1.

As explained above, in accordance with the embodiment of this invention,the number of connection terminals used in electrically connecting thebattery pack with respect to the electronic equipment is reduced. Thus,it is possible to realize miniaturization and avoid unsatisfactoryterminal contact.

Namely, in the embodiments of this invention, the B-IN terminal whichwas conventionally required can be eliminated, and miniaturization ofthe connector by reduction in the number of terminals can be realizedand there can result more reliable contact of the terminal.

This invention is not limited to the above-mentioned embodiments.

While the example of the so-called notebook personal computer ismentioned as the electronic equipment in the above-describedembodiments, this invention is not limited to such implementation. Thisinvention is not limited to notebook personal computers, but may beutilized in equipment for which the supply of power is required by abattery pack. Thus, this invention can be applied to other kinds ofcomputers, information terminals, sound recorders, video tape recorders,portable telephones, electric bicycles and other equipment for which abattery pack is required.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventor to embody withinthe patent warranted hereon all changes and modifications as reasonablyand properly come within the scope of their contribution to the art.

What is claimed is:
 1. A battery pack adapted to be detachably loadedthrough an electric connection portion with respect to an electronicequipment to thereby carry out power supply to the electronic equipment,comprising:a communication line for carrying out transmission/receptionof information between the battery pack and the electronic equipmentused to detect whether the battery pack is in a state electricallyconnected to the connecting portion of the electronic equipment or in astate electrically taken out from the connecting portion of theelectronic equipment, wherein the communication line includes a dataline for carrying out transmission/reception of data between the batterypack and the electronic equipment and a clock line supplied with a clocksignal from the electronic equipment to detect, on a basis ofcombination of states of signals on the data line and the clock line,whether the battery pack is in the state electrically connected to theconnecting portion of the electronic equipment or in the stateelectrically detached from the connecting portion of the electronicequipment.
 2. A battery pack as set forth in claim 1, wherein whetherthe battery pack is in the state electrically connected to theconnecting portion of the electronic equipment or in the stateelectrically detached from the connecting portion of the electronicequipment is detected depending upon presence or absence of a signal onthe data line or the clock line when the electronic equipment issupplied with power and communication is being carried out between thebattery pack and the electronic equipment.
 3. A battery pack as setforth in claim 1, wherein whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment is detected on a basis of a changeof a signal level of the clock line or the data line at a time of afirst state where power supply line connected to the data line and theclock line of the electronic equipment is caused to have high impedance,the electronic equipment is supplied with power and communication is notcarried out between the battery pack and the electronic equipment, achange of the signal level of the data line or the clock line at thetime of a second state where the electronic equipment is supplied withpower and communication is being carried out between the battery packand the electronic equipment, and change of a signal level of the clockline or the data line at the time of a third state where the electronicequipment is not supplied with power.
 4. A battery pack as set forth inclaim 1, wherein whether the battery pack is in the state electricallyconnected to the connecting portion of the electronic equipment or inthe state electrically detached from the connecting portion of theelectronic equipment is detected on a basis of a change of the signallevel of the clock line or the data line at the time of a first statewhere power supply line connected to the data line and the clock line ofthe electronic equipment is caused to have low impedance, and theelectronic equipment is supplied with power and communication is notcarried out between the battery pack and the electronic equipment, achange of the signal level of the data line or the clock line at thetime of a second state where the electronic equipment is supplied withpower and communication is being carried out between the battery packand the electronic equipment, and a change of the signal level of thedata line or the clock line at the time of a third state where theelectronic equipment is not supplied with power.
 5. A battery pack asset forth in claim 1, wherein whether the battery pack in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment is detected on a basis of a changeof the signal level of the clock line or the data line at the time of afirst state where power supply line of the electronic equipment iscaused to have low impedance at the time of loading of the battery pack,and the electronic equipment is supplied with power and communication isnot carried out between the battery pack and the electronic equipment, achange of the signal level of the data line or the clock line at thetime of a second state where the electronic equipment is supplied withpower and communication is being carried out between the battery packand the electronic equipment, and a change of the signal level of thedata line or the clock line at the time of a third state where theelectronic equipment is not supplied with power.
 6. A battery pack asset forth in claim 1, wherein the communication line includes a dataline for carrying out transmission/reception of data between the batterypack and the electronic equipment to detect, on a basis of the state ofa signal on the data line, whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 7. A battery pack as set forth inclaim 6, wherein whether the battery pack is in the state electricallyconnected to the connecting portion of the electronic equipment or inthe state electrically detached from the connecting portion of theelectronic equipment is detected depending upon presence or absence of asignal on the data line when the electronic equipment is supplied withpower and communication is being carried out between the battery packand the electronic equipment.
 8. A battery pack as set forth in claim 6,wherein whether the battery pack is in the state electrically connectedto the connecting portion of the electronic equipment or in the stateelectrically detached from the connecting portion of the electronicequipment is detected on a basis of a change of a signal level of thedata line at the time of a first state where the electronic equipment issupplied with power and communication is not carried out between thebattery pack and the electronic equipment, change of signal level of thedata line at a time of a second state where the electronic equipment issupplied with power and communication is being carried out between thebattery pack and the electronic equipment, and a change of a signallevel of the data line at the time of a third state where the electronicequipment is not supplied with power.
 9. An electronic equipment system,comprising:a battery pack and an electronic equipment in which thebattery pack is detachably loaded through an electric connecting portionso that power supply from the battery pack is carried out, wherein thebattery pack detects, by using a communication line for carrying outtransmission/reception of information between the battery pack and theelectronic equipment, whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment. wherein the communication line iscomposed of a data line disposed between the battery pack and theelectronic equipment and adapted for carrying out transmission/receptionof data, and a clock line disposed between the battery pack and theelectronic equipment and supplied with clock therethrough, and thebattery pack detects, on the basis of combination of states of signalson the data line and the clock line, whether the battery pack is in thestate electrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 10. An electronic equipment systemas set forth in claim 9, wherein the battery pack detects, dependingupon presence or absence of a signal on the data line or the clock linewhen power is supplied from the battery pack to the electronic equipmentas an initial state in electrically connecting the battery pack to theelectronic equipment and communication is being carried out between thebattery pack and the electronic equipment, whether the battery pack isin the state electrically connected to the connecting portion of theelectronic equipment or in the state electrically taken out from theconnecting portion of the electronic equipment.
 11. An electronicequipment system as set forth in claim 9, wherein the battery packdetects, on a basis of change of signal level of the clock line or thedata line at a time of a first state where the data line and the clockline of the electronic equipment are pulled up to a power supply lineplaced in the state of high impedance, power is supplied from thebattery pack to the electronic equipment as an initial state inelectrically connecting the battery pack to the electronic equipment andcommunication is not carried out between the battery pack and theelectronic equipment, presence or absence of a signal on the data lineor the clock line at a time of a second state where power is suppliedfrom the battery pack to the electronic equipment and communication isbeing carried out between the battery pack and the electronic equipment,and change of signal level of the clock line or the data line at a timeof a third state where power is not supplied from the battery pack tothe electronic equipment, whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 12. An electronic equipment systemas set forth in claim 9, wherein the battery pack detects, on a basis ofa change of a signal level of the clock line or the data line at a timeof a first state where the data line and the clock line of theelectronic equipment are pulled up to a power supply line placed in astate of low impedance, and power is supplied from the battery pack tothe electronic equipment as an initial state in electrically connectingthe battery pack to the electronic equipment and communication is notcarried out between the battery pack and the electronic equipment,presence or absence of a signal on the data line or the clock line atthe time of a second state where power is supplied from the battery packto the electronic equipment and communication is being carried outbetween the battery pack and the electronic equipment, and change ofsignal level of the data line or the clock line at the time of a thirdstate where power is not supplied from the battery pack to theelectronic equipment, whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 13. An electronic equipment systemas set forth in claim 9, wherein the battery pack detects, on a basis ofa change of a signal level of the clock line or the data line at a timeof a first state where power supply line connected to the data line andthe clock line of the electronic equipment is caused to have lowimpedance at a time of loading of the battery pack, and power issupplied from the battery pack to the electronic equipment as a initialstate in electrically connecting the battery pack to the electronicequipment and communication is not carried out between the battery packand the electronic equipment, presence or absence of a signal on thedata line or the clock line at the time of a second state where power issupplied from the battery pack to the electronic equipment andcommunication is being carried out between the battery pack and theelectronic equipment, and change of signal level of the data line or theclock line at a time of a third state where power is not supplied fromthe battery pack to the electronic equipment, whether the battery packis in the state electrically connected to the connecting portion of theelectronic equipment or in the state electrically detached from theconnecting portion of the electronic equipment.
 14. An electronicequipment system as set forth in claim 9, wherein the communication lineis disposed between the battery pack and the electronic equipment andcomprised of a data line for carrying out transmission/reception of datato detect, on a basis of a state of a signal on the data line, whetherthe battery pack is in the state electrically connected to theconnecting portion of the electronic equipment or in the stateelectrically detached from the connecting portion of the electronicequipment.
 15. An electronic equipment system as set forth in claim 14,wherein the battery pack detects, in accordance with presence or absenceof a signal on the data line when power is supplied from the batterypack to the electronic equipment as an initial state in electricallyconnecting the battery pack to the electronic equipment andcommunication is being carried out between the battery pack and theelectronic equipment, whether the battery pack is in the stateelectrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 16. An electronic equipment systemas set forth in claim 14, wherein the battery pack detects, on a basisof change of signal level of the data line at a time of a first statewhere power is supplied from the battery pack to the electronicequipment as an initial state in electrically connecting the batterypack to the electronic equipment and communication is not carried outbetween the battery pack and the electronic equipment, presence orabsence of a signal on the data line at the time of a second state wherepower is supplied from the battery pack to the electronic equipment andcommunication is being carried out between the battery pack and theelectronic equipment, and a change of a signal level of the data line atthe time of a third state where no power is supplied from the batterypack to the electronic equipment, whether the battery pack is in thestate electrically connected to the connecting portion of the electronicequipment or in the state electrically detached from the connectingportion of the electronic equipment.
 17. A loading detection method forbattery pack, which is adapted to detachably carry out loading of abattery pack through an electric connecting portion with respect to anelectronic equipment to thereby carry out power supply to the electronicequipment,wherein the battery pack detects, by using a communicationline for carrying out transmission/reception of information between thebattery pack and the electronic equipment, whether the battery pack isin the state electrically connected to the connecting portion of theelectronic equipment, or in the state electrically detached from theconnecting portion of the electronic equipment, wherein thecommunication line is composed of a data line for carrying outtransmission/reception of data between the battery pack and theelectronic equipment and a clock line supplied with clock from theelectronic equipment to detect, on a basis of a combination of states ofsignals on the data line and the clock line, whether the battery pack isin the state electrically connected to the connecting portion of theelectronic equipment or in the state electrically detached from theconnecting portion of the electronic equipment.
 18. A loading detectionmethod for battery pack as set forth in claim 17, wherein thecommunication line is comprised of a data line for carrying outtransmission/reception of data between the battery pack and theelectronic equipment to detect, on a basis of a state of a signal on thedata line, whether the battery pack is in the state electricallyconnected to the connecting portion of the electronic equipment or inthe state electrically detached from the connecting portion of theelectronic equipment.